1. Field of the Invention
The invention relates in general to a digital-to-analog (D/A) converter, and more particularly to a digital-to-analog converter capable of obtaining an analog value corresponding to a part of numeric range of a digital value by way of interpolation.
2. Description of the Related Art
Liquid crystal display has been widely used in the display of various electronic products including TV, computer monitor, notebook computer, mobile phone and digital personal assistant. The data driver of liquid crystal display comprises a digital-to-analog (D/A) converter and a scan driver, wherein the D/A converter provides a pixel voltage to the liquid crystal display according to the gray level, and the scan driver scans the pixel voltage to each pixel of the liquid crystal display for displaying the desired image.
As the relationship between the pixel voltage and the corresponding gray level is non-linear, the conventional D/A converter converts the gray level into a pixel voltage by a Gamma voltage resistor string, and then inputs the pixel voltage to a liquid crystal display. However, as consumers are expecting higher display quality of liquid crystal display, the gray level has more bits and the grade of Gamma voltage resistor string also increases. Thus, the D/A converter will have large area circuit, hence incurring high cost. The conventional method of performing interpolation of each digital code to reduce the cost of the D/A converter is disadvantaged by higher error in pixel voltage and low display quality of liquid crystal display.